BMW i3: Cheap, mass-produced carbon fiber cars finally come of age

The difficulty of working with carbon fiber

Dr. Jorg Pohlmann, managing director of AGL SCF, “In Moses Lake, we treat the acrylic fiber precursor with something of a time and temperature process. We treat the material at different temperatures, first in an oxidation oven. The second step is the actual carbonization at temperatures of up to 1400 degrees Celsius. The material loses about half its weight and gains its incredible material properties. Then it goes to Wackersdorf, where it turns into fabric, almost like a carpet roll.”

Each carbon fiber part comprises 7 to 11 layers of fabric. It’s cut into 2D shapes. Several small cuttings may be formed into one larger part. 3D presses in the Leipzig facility create the near final component. With the RTM (resin transfer molding) press closed, air is extracted, resin is injected under high pressure, and the part is quickly formed. When it comes out, edges are trimmed with a water jet. The outer layer is the car’s body color, so there’s no separate painting step, which is one of a traditional factory’s biggest water- and energy-consumers.

According to Schafer, careful control of the process steps, especially temperature and pressure, speeds up the work, so parts-forming might take minutes not hours. BMW uses a special glue to combine parts that can be positioned normally, but as soon as heat and pressure are applied, the curing process speeds up by a factor of 32.

There are about 45 CFRP components in the i3, of which the biggest are the left and right side body panels.

BMW also turned to Boeing as a technology partner because of its 30-year experience developing parts for the Boeing 777 and for the fuselage and wings of the carbon fiber Boeing 787 Dreamliner. Larry Schneider, a Boeing VP for product development, said, “CFRP’s main advantage is weight savings … we’re trying to get 20% fuel savings on the 787. In addition, it helps from a durability standpoint such as nuisance impacts around the airport [jetway banging into the fuselage] … and also the corrosion and fatigue characteristics.”

Take that, Prius: BMW’s green technologies

BMW knocked itself out making the car be at one with the environment. It says a quarter of the interior plastics and the exterior thermoplastics are recycled or renewable. Take the bio-polymer ignition key: It’s based on castor oil from castor seeds. The dashboard wood is “responsibly forested” eucalyptus. The instrument panel surround and door trim contain fibers from the Kenaf plant native to Africa. The leather is tanned with olive-leaf extract. BMW notes, “The owner’s manual is also made from renewable sources.” That might also be called “paper,” most likely printed with soy inks and without a glossy cover. At end-of-life, most of the components of the i3 can be recycled, including the carbon fiber body panels.

Other automakers carbon fiber plans

The world’s automakers are all researching and investing in carbon fiber. It may help them meet stricter fuel economy and crash safety standards. Ford created a joint venture with Dow Chemical with the goal of mass production of carbon fiber components by 2020. General Motors partnered with Teijin of Japan to create carbon fiber parts; Teijin set up a tech center in Detroit to be close to GM. Chrysler has been building low-volume carbon fiber parts such as the hood of the Dodge Viper and claims a small triumph: The carbon fiber hood is cheaper to make than the fiberglass hood it replaces. Alternative fabrication techniques could cut costs more. Rather than use long strands of carbon fiber filament, it’s possible to mold chopped fibers with all the lightness and about two-thirds of the strength, which may be good enough for a part that isn’t crucial to crash absorption, such as a trunk lid.

I do think it is lost on many people that the Carbon Fiber and Aluminum chassis will find their way into other BMW models to make them lighter and have better performance.

A modern EV that comes in at $2700 pounds is amazing…

Bill Howard

If BMW can get a jump of 1, 3, 5 years on the competition building carbon fiber panels into mainstream cars, it’s a huge advantage. They could also go to plastic for lowly stressed parts (the decklid) or as the story notes, use chopped fiber that has 1/3 less strength but lower mfg cost. Some of the process steps BMW is using take minutes where older techniques took hours.

I have owned two old, used cars that weighed less than 2500 pounds, a VW Beetle that was not a paragon of safety, and a Mini Cooper knockoff Fiat 128 that got lighter each year through a Fiat technology called rust perforation.

Phil

So they ‘minimize energy costs’ by doing cute things like putting the carbon fiber factory near a lake…

And then they ship that carbon fiber across the globe to assemble it.

That’s called a gimmick.

Bill Howard

The light carbon fiber material gets shipped to Europe where they get produced into the body panels that become heavier (resin injection in the molding) and bulkier.BMW agrees the energy expenditure in creating the CRFP panels is more than for a metal body car. BMW says the total lifecycle costs including fuel (electricity) to run the car and what you get back when the car is recycled a decade or so from now, that will be lower.

Lower hanging fruit might be to wonder why the PRC buys scrap iron from the US, re-refines it over there, and sends it back to us as new steel. (Part of the answer may be you have more empty hulls going west across the Pacific once they’ve dropped off their loads of furniture, TVs, cars, etcetera, so why not.)

Phil

The shipping industry is pretty baffling in its mammoth size.

jfreed27

Agreed. Greenwashing with a ‘happy face’

Nic Phillips

It’s not “CHEAP” carbon fiber, it’s INEXPENSIVE

Steve Hawken

The most important points and USB of these cars are its light weight and fuel efficiency. The chassis of these cars would be very lighter and hence will give a better control for the drivers and will also save a lot on the weight and at the same time wouldn’t compo on the safety as these cars with Carbon Fiber or Aluminum body are stronger then its predecessors and also comes at lower price. That is why most of the car makers are replacing the body with this new tech.http://www.euroautomotive.net/

jfreed27

Amory Lovins touts carbon fibre as the next giant step in lower oil use. Glad to see it is coming to market.

Kosenefx

$40k + .. think I’ll buy 2 seeing they are so CHEAP ?? NOT

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